Gas turbine engines are typically employed to power aircraft. Typically a gas turbine engine will comprise an axial fan driven by an engine core. The engine core is generally made up of one or more turbines which drive respective compressors via coaxial shafts. The fan is usually driven via one of the turbines.
The fan may comprise an array of radially extending fan blades mounted on a rotor. The fan blades may be manufactured from metallic or composite materials. Generally composite fan blades include a body formed from a plurality of composite structured plies that include fibres within a resin matrix.
During operation of the gas turbine engine, the fan blades may be impacted by a foreign object (such as a bird) or if a failure occurs the fan blade may be impacted by another fan blade that has been released from the remainder of the fan. In such impact events the integrity of the fan blade should be maintained. A failure mechanism of concern for composite fan blades is delamination.
To resist delamination the fan blade may be reinforced. One method of reinforcing a composite component such as a fan blade is to use through thickness reinforcement rods or pins.
U.S. Pat. No. 8,893,367, which is incorporated herein by reference, discloses a method by which reinforcement rods can be positioned in a composite component. In the method described in U.S. Pat. No. 8,893,367, a composite material is heated and holes are formed in the material, reinforcement elements are then provided in each of the holes.